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How could I have gotten psoriasis?

Happy family
Psoriasis runs in families: If a parent, grandparent, brother, or sister has psoriasis, you have a higher risk of getting psoriasis.
Psoriasis is not contagious. Unlike a cold or the flu, you cannot catch psoriasis from someone. You cannot get it from swimming in a pool with someone who has psoriasis. When you touch someone who has psoriasis, you cannot get it. If you have sex with someone who has psoriasis, it’s not possible to get it.

While we know that psoriasis isn’t contagious, what causes it is still a bit of a mystery. It appears that a person’s genes, immune system, and environment are involved.

Genes: We know that psoriasis runs in families. If a close blood relative has psoriasis, you have a higher risk of getting it. Though not everyone who has a family member with psoriasis will get psoriasis.

Immune system: When you have psoriasis, your white blood cells attack your skin cells. White blood cells, also called T cells, are part of the immune system. These cells help the body fight off germs such as bacteria and viruses. When you have psoriasis, something goes wrong and your T cells start attacking your skin cells.

Environment: If you have psoriasis genes, it seems that something must trigger these genes for you to get psoriasis. Plenty of everyday things can do this, including:

  • Stress

  • Skin injury

  • Infection

  • Some medications, including lithium, prednisone, and medication taken to prevent malaria 

  • Weather (especially very cold weather)

  • Smoking

  • Drinking heavily

Different people have different triggers. For example, periods of intense stress may trigger your psoriasis but cold weather may not. 

If you have psoriasis, it’s important to learn what triggers it. Avoiding your triggers can reduce psoriasis flares.

Image from Getty Images

van de Kerkhof PCM and Schlkwijk J. (2008) “Psoriasis.” In: Bolognia JL, Jorizzo JL, et al. editors. Dermatology, 2nd ed. Spain, Mosby Elsevier: p. 115.